Use of embryo culture supernatant to improve clinical outcomes in assisted reproductive technology: a systematic review and meta-analysis.

We planned a systematic review and meta-analysis of randomized clinical trials (RCTs) to examine the best available evidence regarding the intrauterine instillation of embryo culture supernatant prior to embryo transfer in ART. The outcomes were: (i) live birth; (ii) clinical pregnancy; (iii) multiple pregnancy; and (iv) miscarriage rates. Five RCTs were considered eligible and available for qualitative synthesis. Due to clinical heterogeneity, results from only two trials were combined for the meta-analysis. The live birth rate (risk ratio [RR], 0.47; 95% confidence interval [CI] 0.22-0.98; one study, 60 participants, low-quality evidence) was found to be significantly lower with intrauterine instillation of embryo culture supernatant compared to no intervention. The clinical pregnancy rate was similar between the embryo culture supernatant group and the control group (RR 1.02 RR, 95% CI 0.77-1.36; two trials, 156 participants, <italic>I</italic>2 = 0%). To conclude, this review did not find any improvement in clinical pregnancy rate with the intrauterine instillation of embryo culture supernatant prior to embryo transfer compared to no intervention in women undergoing ART and we remain uncertain regarding its effect on live birth rate. [ABSTRACT FROM AUTHOR]